This invention relates to methods and apparatuses for providing navigation information to the pilot of an aircraft, in particular, to providing the pilot with information regarding whether the aircraft can safely glide to a landing site in the absence of power.
All too often, an aircraft loses power in flight for one reason or another. When this happens, it is important for the pilot to know the landing sites to which the pilot can safely glide. However, in such anxiety-provoking circumstances it is often difficult for the pilot to make the necessary calculations, at least to do so in a timely fashion.
Various kinds of electronic navigation aids have previously been disclosed. It is well understood that electronic altimeters are available for providing a signal representative of the current altitude of an aircraft. Loran systems also provide electronic data representative of the current lateral position of the aircraft.
Hendrickson U.S. Pat. No. 4,220,994 discloses a system that stores information regarding the location of airports and VOR stations, transmitting frequencies, and aircraft running characteristics, and executes programs for preparing flight plans and resolving common navigational problems such as dead reckoning, wind effect, bearing correction, fuel consumption, and for generating flight profile data for fuel optimization. Thurman U.S. Pat. No. 4,706,198 discloses an air traffic control system that communicates with an aircraft and computes flight plans based upon the position of the aircraft. Fischer U.S. Pat. No. 4,674,051 discloses a system that uses aircraft position data to look up the closest navigation point and information about that point in an electronic look up table. James et al U.S. Pat. No. 4,283,705 discloses a combined, heading, altitude, and horizontal situation display device. Forsythe et al. U.S. Pat. No. 4,212,064 U.S. Patent discloses a system for displaying optimum altitude, air speed, and other settings for achieving flight economy. However, none of these navigational aids tells the pilot whether the aircraft can safely glide to a selected landing sight, what the minimum required altitude is for a safe glide, or what the margin of safety is.
It would therefore be desirable to have a method and apparatus that would automatically provide the desired information to the pilot upon the occurrence of a loss of power.